Page for that keyword listing is gone.

Well If i searched for a certain keyword in google a page of my website was on the top 10, now I can't find that page for this keyword anymore but I can see that page for other keywords.

What does this mean?

 

firstly check you grammar before publishing..

this happens because there are better sites offering better content (as per Google's algo) for that keyword. So your site goes down and other sites come up.

 

I mean it doesn't appear at all for that keyword.

 

Sometimes this will happen when you get a new link with exact anchor text for that page, natural or not. It will usually disappear for a day or two and then return somewhere in the general area of the listings, depending on the value of the link. Normal as of late.